You might find this interesting.
While the population growth has slowed slightly there is no statistic I have seen that shows it "going down" at any point. Even with the many Covid deaths in the last 2 years.
Also regarding my first point, the following article is just one of many written over the last two decades regarding food quality decline. This one appeared in Scientific American on April 27th, 2011.
Have Fruits and Vegetables Become Less Nutritious?
There are also many reports and research papers written on fertilizers and groundwater contamination.